Variable coil assembly



Dec. 22, 1953 W. L. VERVEST ET AL VARIABLE COIL.

Fil ed April ASSEMBLY INVENTORS Gozewijn yon Gelder Wilhelmus Lombertus Vervesf Agent Patented Dec. 22, 1953 VARIABLE COIL ASSEMBLY Wilhelmus Lambertus Ver Gelder, Hilversum, Net Hartford National Ban Hartford, Conn., as trus vest and Gozewijn van herlands, assignors to k and Trust Company, tee

Application April 3, 1952, Serial N 0. 280,408

Claims priority, application Netherlands April 23, 1951 3 Claims. 1

This invention relates to a variable coil assembly. More particularly, the invention relates to a coil assembly comprising a helical or spiral winding which is rotatable about its axis and over which a contact member is displaceable.

It is an object of the invention to provide a novel form of coil assembly which rotates in one direction only and in which the resistance or inductance of the coil is continuously variable.

This and other objects of the invention will be best understood from the following description.

According to the invention the coil winding is arranged to rotate While a contact, axially displaceable, moves in engagement with the coil. At the end of its travel, the contact is lifted off the coil, locked to prevent reengagement with the coil, and returned to its initial position where it reengages the coil again.

In a preferred embodiment of the invention, the

contact is carried on a guide rod having a projection which fits into a corresponding recess of an arm supported by a coil frame which looks the contact against reengagement after the latter reaches the end of the coil.

The invention will now be described with reference to the accompanying drawing in which:

Fig. 1 is a side view of one form of coil assembly in accordance with the invention, with a side wall removed;

Fig. 2 is a view, in cross-section, along line II-II of Fig. 1;

Fig. 3 is a view similar to Fig. 1 of the right side of the coil assembly at a different stage of operation.

Fig. 4 is a view of a part of another form of coil assembly in accordance with the invention.

Referring to Figs. 1 and 2, a coil assembly comprises a rotatable coil winding I mounted on an insulating drum 3. The drum 3 is fitted on a metal shaft 5 journalled in two insulating end plates I, 9, of a frame. A second shaft I I is journalled in the end plates 1, 9, which shaft II constitutes the axis of rotation of a swing comprising two arms i3 and i5 pivotably secured to the shaft I I and interconnected at their free ends by a third shaft IT.

The shaft I1 carries a freely rotatable and displaceable metal contact roller I9, the periphery of which is provided with a race I9 for contact engagement with the wire of the winding I. Tension springs 2 I, 23 (for the sake of clearness Fig. 1 shows only spring 2!), each having one end. fixed to the end plates I, 9, respectively, are affixed to the free ends of the arms I3 and it: at opposite ends of the shaft II, so that the contact roller I9 engages the winding I with the desired contact pressure.

The inductance or resistance of the coil is variable in the usual manner by rotation of shaft the roller I9 moving along shaft II-in Fig. 1 to the left-and the winding I, consequently, acting as a screw thread.

At the end of winding I, the wire is bent thus forming a lug-shaped protuberance (Fig. 2). When the roller I9 reaches this lug, the shaft I1 is depressed and turns through a small angle about shaft II against the action of the springs 2 I, 23.

Adjacent the arm I5 is a locking member 2'! which is rotatable about a shaft 29 which is affixed to the adjacent end plate 9. The locking member 2'! is biased by a spring 3I in the direction of the arm I5. The arm 21 is provided with a recess 33 which is adapted to interfit with the arm I5 in the depressed position of shaft IT, in which position the arm I5 is locked.

When shaft 5 is rotated a little further, the roller I9 comes clear of lug 25 and is moved to the right (Fig. 1) by the action of a compression spring 35 provided on shaft I'I. Referring to Fig. 3, just before the roller I9 resumes its initial position at the end of its return movement, the roller I9 engages a shoulder 31 provided at the end of the locking arm 21. The impact of the moving roller I9 is suflicient to cause the arm 27 to be forced to the right against the pressure of spring 3I. The movement of the arm 21 to the right releases the arm I5 and the roller I9 resumes its initial position in which it is in contact engagement with the winding I. Hence, the shaft 5 is always rotatable in the same direction.

Two contact springs 39, 4| engage the ends of shafts 5 and I I and act as supply contacts therefor. The beginning of winding I is connected to the shaft 5.

Fig. 4 shows an arrangement using a flat spiral winding 51, the contact roller 53 then moving in a radial instead of an axial direction with respect to the shaft 55 of the insulating supporting disc 51 to which the winding 5I is fastened. In the embodiment shown in Fig. 4, furthermore, the screw thread does not consist of the wire itself, but a groove 59 is cut into the disc 57 between the turns of the coil 5I and a scanning finger, in this case a flange 6| is provided on the contact roller 53 to engage the groove 59 and cause the roller 53 to move in its axial direction i. e. radially to the disc 51, along the coil. At the end of their movement, the roller 53 and the scanning flange (H are lifted off from the winding SI and the is obvious that the contact roller may also engage the inner side of the coil winding.

Again in Fig. 1 means (not shown) may be provided to rigidly support the shaft 5 and the winding I and further means to rotate the rest of the device around said shaft.

While the invention has been described in connection with specific examples and in specific application, other modifications thereof will be readily apparent to those skilled in the art without departing from the invention as defined in the appended claims.

What we claim is:

1. A continuously variable coil assembly comprising a continuously rotatable winding, a contact member in engagement with said winding and arranged to follow along the winding as the winding is rotated, means for lifting the contact .member oif said winding, locking means for preventing the contact member from re-engaging said winding after it is lifted ofi, means for restoring the contact member to its initial position,

and means for releasing the contact member so that it re-engages the winding.

2. A continuously variable coil assembly comprising a continuously rotatable helical winding, a contact member in engagement with said wind ing and arranged to follow along the winding as the latter rotates, a protuberance provided at the end of said winding to move said contact member away from engagement with the remainder of said winding, a locking member for holding said contact member away from engagement with said winding, means for restoring said contact member to its initial position while it is held away from engagement with said winding by said looking member, and means for releasing said locking memberby said contact member when this member reaches its initial position, so that said contact member re-engages said winding.

3. A continuously variable coil assembly comprising a continuously rotatable helical winding, 2. displaceable contact member in engagement with said winding, a pivotable guide rod on which said contact member is supported, biasing means secured to said guide rod for maintaining said contact member in engagement with said winding, a protuberance on the end of said winding to move said contact member away from engagement with said winding against the action of the biasing means when said contact member reaches the end of the winding, a locking member adapted to interfit with the end of said guide rod when said guide rod is moved a given distance by said protuberance and to hold said guide rod spaced by the given distance from said winding, a restoring member to cause said contact member to be displaced along said guide rod to the opposite end of the winding when said contact member is moved away from engagement with said winding, said locking member being shaped such that it is engaged by the returning contact member to thereby release the guide rod and cause the contact member to re-engage the winding.

WILHELMUS LAM'BERTUS VEBVEST. GOZEVJIJN VAN GELDER.

No references cited. 

